Little is known about the distribution of dark energy, but dark matter is certainly not homogeneous in the Universe, except at very large scales. Therefore, it's is not a simple balance problem.

Dark matter is unobserved matter that was hypothesised because the rotation profiles of galaxies seem to suggest that some sort of unobserved matter around galaxy haloes. No one knows what dark matter really is, but some people think that rotation profiles can be solved by considering alternative theories of gravity, like MOdified Newtonian Gravity (MOND).

Energy is something that is exchanged in most physical processes. Dark energy is energy that is unaccounted for by known phenomena and was hypothesised because SN 1a observations seem to suggest that the expansion of the Universe is accelerating, which is not accounted for in the vanilla Big Bang model. No one knows what dark energy really is.